1. Field of the Invention
The present invention relates to a variable venturi type carburetor and, more particularly, to a variable venturi type carburetor which can diminish the fluctuation of air-fuel ratio when the flow rate of intake air is small and can stabilize the idling operation of engine.
2. Description of the Prior Art
Recently, such a technique has been developed as to make it possible to operate engines with a lean mixture and to obtain a stable idling operation at reduced speed, in order to achieve a fuel economy. In conventional carburetors, these aims are achieved by improving the slow fuel system. However, in variable venturi type carburetors in which the air-fuel ratio is controlled through the control of the annular area between a main jet and a metering needle, the provision of the slow fuel system often results in impaired driveability because of difficulty in adaptation of the main jet to the metering needle and inadequate transient characteristics between the slow region and main region.